JP7552891B2 - Drive unit - Google Patents

Description

The present invention relates to a drive unit for a series hybrid vehicle.

JP2017-216804A discloses a drive device for a vehicle that has a generator fastened to a transmission and having a first housing, and a drive machine fastened to the transmission and having a second housing, and is fastened to an engine. In a drive device in which the generator and drive machine are housed in separate housings like this, the two housings vibrate separately, and there is a problem that vibrations become larger due to bending or twisting of the generator and drive machine. There is also a problem that resonance is easily generated by the two vibration sources being close to each other. To solve these problems, the above document connects the first housing and the second housing with a connecting member.

However, the drive device disclosed in the above document only connects parts of the first and second housings, which each vibrate separately, so the vibration suppression effect is limited.

Therefore, the present invention aims to provide a drive unit with further improved vibration suppression effect.

According to one aspect of the present invention, a drive unit is provided having an electric unit including a first electric motor for driving, a reduction mechanism that transmits the rotational torque of the first electric motor to a drive wheel, a second electric motor that is driven by an internal combustion engine to generate electricity, and a speed-up mechanism that transmits the rotational torque of the internal combustion engine to the second electric motor. In this drive unit, the first electric motor, the reduction mechanism, the second electric motor, and the speed-up mechanism are housed in one housing. In the housing, the first electric motor and the second electric motor are arranged in the longitudinal direction of the vehicle body with their respective rotation axes parallel to each other, and the reduction mechanism and the speed-up mechanism are arranged in the longitudinal direction of the vehicle body. The electric unit and the internal combustion engine are connected in a state where they are arranged in the transverse direction of the vehicle body, and the first rotation shaft, which is the rotation shaft of the first electric motor, and the second rotation shaft, which is the rotation shaft of the second electric motor, are located on the front and rear sides of the longitudinal direction of the vehicle body, sandwiching the crankshaft rotation axis, which is the rotation shaft of the crankshaft of the internal combustion engine.

FIG. 1 is a schematic diagram of a drive unit mounted on a vehicle, as viewed from above the vehicle body. FIG. 2 is an exploded perspective view of an electric unit included in the drive unit. FIG. 3 is a side view of the electric unit as viewed from the direction of arrow III in FIG.

Below, an embodiment of the present invention is described with reference to the drawings.

Figure 1 is a schematic diagram of the drive unit 100 according to this embodiment when mounted on the vehicle and viewed from above the vehicle body. Figure 2 is an exploded perspective view of an electric unit 100a included in the drive unit 100. Figure 3 is a side view of the electric unit 100a as viewed from the direction of arrow III in Figure 2.

In the following explanation, the direction of vehicle travel is referred to as "front", the opposite direction as "rear", the left side of the vehicle travel direction as "left", the right side as "right", the upper side as "up" and the lower side as "down".

The drive unit 100 comprises an internal combustion engine 1 and an electric unit 100a, which will be described later. The internal combustion engine 1 is arranged with the crankshaft 1a oriented in the same direction as the left-right direction of the vehicle body. The electric unit 100a is aligned with the internal combustion engine 1 in the left-right direction of the vehicle body. The internal combustion engine 1 and the electric unit 100a are fastened together with bolts or the like. An auxiliary part 6 is attached to the internal combustion engine 1. The auxiliary part 6 is, for example, an oil cooler, a compressor for an air conditioning system, etc.

The fastened internal combustion engine 1 and electric unit 100a (i.e., drive unit 100) are supported on the vehicle body from the left and right directions of the vehicle body by pendulum-type mounts 2a and 2b. Here, the support parts of mounts 2a and 2b are designated as 3a and 3b, respectively. In addition to mounts 2a and 2b, a torque rod (not shown) may be provided that supports drive unit 100 from the front and rear directions of the vehicle body.

Here, the configuration of the electric unit 100a will be explained with reference to Figure 2.

The housing H of the electric unit 100a is composed of an outer housing 10, a gear cover 11 attached to one end of the outer housing 10, and a rear cover 12 attached to the other end of the outer housing 10.

The outer housing 10 includes a first cylindrical portion (not shown) in which the drive motor 15 is housed, and a second cylindrical portion (not shown) in which the generator motor 17 is housed. The first cylindrical portion and the second cylindrical portion are each formed in a cylindrical shape, and are provided in the outer housing 10 with their axes aligned parallel to each other. The first cylindrical portion houses the drive motor 15 as a first electric motor via the inner housing 14, and the second cylindrical portion houses the generator motor 17 as a second electric motor via the inner housing 16. Comparing the drive motor 15 and the generator motor 17, the drive motor 15, which requires a larger output, is heavier than the generator motor 17.

The drive motor 15 includes a rotor 15a rotatably supported by the rear cover 12, and a stator (not shown) fixed inside the inner housing 14. The generator motor 17 includes a rotor 17a rotatably supported by the rear cover 12, and a stator (not shown) fixed inside the inner housing 16. The inner housings 14, 16 and the rear cover 12 are fixed to the outer housing 10 by bolts or the like, so that the rotors 15a, 17a and the stator are fixed in opposing positions.

The inverter 13 is mounted on the upper part of the outer housing 10. The inverter 13 includes a first power module 40 and a second power module 41 that constitute an inverter circuit. The upper part here refers to a part above a plane including the first rotating shaft 15b, which is the rotating shaft of the drive motor 15, and the second rotating shaft 17b, which is the rotating shaft of the generator motor 17. In this embodiment, the electric unit 100a is mounted on the vehicle in a state in which the plane P including the first rotating shaft 15b and the second rotating shaft 17b is inclined with respect to the horizontal direction, as shown in FIG. 3 described later. More specifically, the electric unit 100a is mounted on the vehicle in a state in which the drive motor 15 is inclined so that it is positioned higher than the generator motor 17.

The gear chamber G formed by the outer housing 10 and the gear cover 11 accommodates a reduction mechanism 18 connected to the rotating shaft 15b of the drive motor 15 and a speed increase mechanism 19 connected to the rotating shaft 17b of the generator motor 17.

The reduction mechanism 18 is composed of three gears, and transmits the rotation of the rotating shaft 15b of the drive motor 15 to the drive wheels (not shown). The output shaft 5 of the reduction mechanism 18 and the drive wheels are connected via a drive shaft (not shown). The output shaft 5 is arranged perpendicular to the traveling direction of the vehicle due to its nature. The rotating shafts of the gears of the reduction mechanism 18 and the first rotating shaft 15b that inputs rotation to the reduction mechanism 18 are parallel to the output shaft 5. The second rotating shaft 17b, which is parallel to the first rotating shaft 15b, is also parallel to the output shaft 5. Furthermore, the crankshaft 1a of the internal combustion engine 1, which is connected to the second rotating shaft 17b via the speed increasing mechanism 19, is also parallel to the output shaft 5.

The speed increasing mechanism 19 increases the rotation of the crankshaft 1a of the internal combustion engine 1 and transmits it to the generator motor 17. In this embodiment, the speed increasing mechanism 19 is exemplified by a mechanism using a sprocket and a chain as shown in Figure 3, but it may also be a mechanism consisting of two gears.

In addition, when comparing the speed reduction mechanism 18 and the speed increase mechanism 19, the speed reduction mechanism 18, which is composed of three gears, is heavier than the speed increase mechanism 19, which is composed of two sprockets and a chain or two gears.

As described above, the electric unit 100a of this embodiment has four elements, namely, the drive motor 15, the speed increasing mechanism 19, the generator motor 17, and the speed reducing mechanism 18, housed in a single housing H. Furthermore, the housing H also has an inverter 13 mounted thereon.

Return to the explanation of Figure 1.

The crankshaft rotation axis 1b is parallel to the mount connection Amt that connects the support parts 3a, 3b of both mounts 2a, 2b, and is on a vertical plane S that includes the mount connection Amt as shown in Figure 3. The mount connection Amt is also parallel to the output shaft 5 of the reduction mechanism 18.

In the drive unit 100 mounted on the vehicle, the first rotating shaft 15b and the second rotating shaft 17b are located at the front and rear in the fore-and-aft direction of the vehicle body, sandwiching the rotating shaft 1b of the crankshaft 1a (also called the crankshaft rotating shaft).

More specifically, the drive motor 15 is disposed rearward of the crankshaft rotating shaft 1b, and the generator motor 17 is disposed forward of the crankshaft rotating shaft 1b. Accordingly, the reduction mechanism 18 is disposed rearward of the crankshaft rotating shaft 1b, and the speed increase mechanism 19 is disposed forward of the crankshaft rotating shaft 1b. As described above, the drive motor 15 is heavier than the generator motor 17, and the reduction mechanism 18 is heavier than the speed increase mechanism 19. For this reason, the center of gravity of the electric unit 100a is located rearward of the crankshaft rotating shaft 1b. Therefore, the auxiliary parts 6 are disposed forward of the crankshaft rotating shaft 1b so that the center of gravity of the drive unit 100 is located on the mount connection Amt when viewed from above the vehicle body. This makes it possible to suppress vibration. Which of the oil cooler, air conditioning compressor, etc. is to be the auxiliary part 6 is appropriately determined based on the weight difference between the drive motor 15 and the generator motor 17, the weight difference between the reduction mechanism 18 and the speed increase mechanism 19, etc.

Here, the positional relationship between the first rotating shaft 15b, the second rotating shaft 17b, and the crankshaft rotating shaft 1b will be described in more detail with reference to Fig. 3. Fig. 3 is a view of the housing H of the electric unit 100a as viewed from the direction along the arrow III in Fig. 2 (i.e., the left-right direction of the vehicle body).

In Fig. 3, the crankshaft rotation axis 1b is located on the motor connection Amg that passes through the first rotation axis 15b and the second rotation axis 17b, and at the midpoint between the first rotation axis 15b and the second rotation axis 17b. It is also desirable that the motor connection Amg be inclined at 45° with respect to the horizontal plane.

In this way, the drive motor 15 and the generator motor 17 are arranged at an angle to the horizontal plane, so that the dimensions of the drive unit 100 in the front-to-rear direction can be reduced. The reason why the inclination is 45° is that it is possible to reduce both the dimensions of the drive unit 100 in the front-to-rear direction and the vertical direction. In other words, if the inclination is greater than 45°, the dimensions in the front-to-rear direction can be reduced more, but the vertical direction dimension will be larger than in the case of 45°, and if the inclination is less than 45°, the vertical direction dimension can be reduced more, but the dimensions in the front-to-rear direction will be larger than in the case of 45°. In contrast, if the inclination is 45°, it is possible to reduce both the dimensions in the front-to-rear direction and the vertical direction.

In addition, since the electric unit 100a is housed in a single housing H, it vibrates as a unit, but the above configuration makes it possible to suppress both vertical and horizontal vibrations of the electric unit 100a. That is, if the inclination is greater than 45°, vertical vibrations can be suppressed more, but front-to-back vibrations will be greater than when the inclination is 45°, and if the inclination is less than 45°, front-to-back vibrations can be suppressed more, but the vertical vibrations will be greater than when the inclination is 45°. In contrast, if the inclination is 45°, it is possible to suppress both vertical and front-to-back vibrations.

Next, we will explain the effects of configuring the drive unit 100 in this embodiment.

In this embodiment, a drive unit 100 is provided that includes an electric unit having a drive motor 15, a reduction mechanism 18 that transmits the rotational torque of the drive motor 15 to the drive wheels, a generator motor 17 that is driven by the internal combustion engine 1 to generate electricity, and a speed-up mechanism 19 that transmits the rotational torque of the internal combustion engine 1 to the generator motor 17. In this drive unit 100, the drive motor 15, the reduction mechanism 18, the generator motor 17, and the speed-up mechanism 19 are housed in a single housing H, and within the housing H, the drive motor 15 and the generator motor 17 are aligned in the fore-and-aft direction of the vehicle body with their respective rotation axes parallel to each other, and the reduction mechanism 18 and the speed-up mechanism 19 are aligned in the fore-and-aft direction of the vehicle body. In addition, the electric unit 100a and the internal combustion engine 1 are connected in a state of being aligned in the left-right direction of the vehicle body, and the first rotating shaft 15b, which is the rotating shaft of the drive motor 15, and the second rotating shaft 17b, which is the rotating shaft of the generator motor 17, are located on the front and rear sides of the crankshaft rotating shaft 1b, which is the rotating shaft of the crankshaft 1a of the internal combustion engine 1, in the front-rear direction of the vehicle body. As described above, by accommodating the drive motor 15 and the generator motor 17, which are the main vibration sources of the electric unit 100a, in one housing H, it is possible to suppress the drive motor 15 and the generator motor 17 from vibrating in individual modes. In addition, by arranging the first rotating shaft 15b and the second rotating shaft 17b in front and rear of the crankshaft rotating shaft 1b of the internal combustion engine 1, which is the heaviest part of the drive unit 100, the center of gravity of the drive unit 100 is located between the first rotating shaft 15b and the second rotating shaft 17b. This makes it possible to suppress vibration of the drive unit 100.

In this embodiment, the electric unit 100a and the internal combustion engine 1 in a connected state are supported on the vehicle body by the pendulum mounts 2a and 2b from the left and right of the vehicle body, and the mount connection Amt, which is a line connecting the support part 3a of the mount 2a on the left side in the left and right direction of the vehicle body and the support part 3b of the mount 2b on the right side in the left and right direction of the vehicle body, is parallel to the output shaft 5 of the reduction mechanism 18. As a result, the crankshaft rotation shaft 1b, the first rotation shaft 15b, the second rotation shaft 17b, and the output shaft 5 are parallel to the mount connection Amt. If these rotation shafts are not parallel to the mount connection Amt, the vibration of the drive unit 100 is transmitted to the vehicle body as so-called torsional vibration, and undesirable vibration occurs in the vehicle body. In contrast, according to the configuration of this embodiment, the torsional vibration can be suppressed.

The mount connection Amt can be parallel to each axis 1b, 15b, 17b, and 5 for the following reasons.

The position of the support part 3b of the mount 2b supporting the internal combustion engine 1 in the vehicle longitudinal direction is preferably close to the center of gravity axis of the internal combustion engine 1 in the vehicle lateral direction from the viewpoint of suppressing the moment around the support part 3b. On the other hand, the position of the support part 3a of the mount 2a supporting the electric unit 100a in the vehicle longitudinal direction is preferably close to the center of gravity axis of the electric unit 100a in the vehicle lateral direction from the viewpoint of suppressing the moment around the support part 3b. However, the generator motor 17 needs to be connected to the internal combustion engine 1 via the speed increasing mechanism 19, and the drive motor 15 and the reduction mechanism 18 need to be arranged to avoid interference with the generator motor 17 and the speed increasing mechanism 19. For this reason, in the conventional configuration in which the drive motor 15 and the generator motor 17 are housed in separate cases, the dimensional deviation in the vehicle longitudinal direction between the electric unit 100a and the internal combustion engine 1 becomes large, making it difficult to make the mount connection Amt parallel to each of the axes 1b, 15b, 17b, and 5.

In this embodiment, by housing the drive motor 15 and the generator motor 17 within the outer housing 10, the dimensions of the electric unit 100a in the fore-and-aft direction of the vehicle body are reduced compared to when each motor is housed in a separate housing.

In addition, when connecting the internal combustion engine 1, the speed-up mechanism 19, and the generator motor 17, in a conventional configuration in which the speed-up mechanism 19 and the generator motor 17 are housed in separate housings, the speed-up mechanism 19 is configured with three gears to avoid interference between the elements in the fore-aft direction of the vehicle body. In other words, the configuration is such that three gears are lined up in the fore-aft direction of the vehicle body. In contrast, in this embodiment, the speed-up mechanism 19 and the generator motor 17 are housed in the outer housing 10, which increases the freedom of layout and allows the speed-up mechanism 19 to be configured with two sprockets and a chain or two gears as described above. As a result, the dimensions of the vehicle body fore-aft electric unit 100a in the fore-aft direction of the vehicle body are smaller than when the speed-up mechanism 19 is configured with three gears.

Furthermore, in this embodiment, the inverter 13 is also housed in the outer housing 10. If the inverter 13 is housed in a housing (inverter housing) separate from the drive motor 15, etc., and this housing is attached to a housing (motor housing) that houses the drive motor 15, etc., the inverter housing will protrude from the motor housing, which tends to increase the overhang in the fore-and-aft direction of the vehicle body. In contrast, in the configuration in this embodiment in which the inverter 13 is also housed in the outer housing 10, the overhang in the fore-and-aft direction of the vehicle body can be reduced.

In this embodiment, by suppressing the vehicle body fore-and-aft dimensions and overhang as described above, it is possible to make the mount connection Amt parallel to each of the axes 1b, 15b, 17b, and 5 while positioning the support portion 3a of the mount 2a in the fore-and-aft direction in a position suitable for supporting the electric unit 100a.

In this embodiment, the crankshaft rotation axis 1b is parallel to the mount connection Amt and lies on a vertical plane S including the mount connection Amt. Since the crankshaft rotation axis 1b of the internal combustion engine 1, which is the heaviest part of the drive unit 100, lies on a vertical plane S including the mount connection Amt, vibration of the drive unit 100 with the supports 3a and 3b as fulcrums can be suppressed.

In this embodiment, the drive motor 15 is heavier than the generator motor 17, the speed increase mechanism 19 is heavier than the speed reduction mechanism 18, the drive motor 15 and the speed reduction mechanism 18 are disposed rearward of the crankshaft rotating shaft 1b, and the generator motor 17 and the speed increase mechanism 19 are disposed forward of the crankshaft rotating shaft 1b. At least a portion of the auxiliary components 6 of the internal combustion engine 1 are disposed forward of the crankshaft rotating shaft 1b, so that the center of gravity of the entire drive unit 100 is located on the mount connection Amt. This allows the drive unit 100 to be balanced in the state supported by the mounts 2a and 2b, and vibration of the entire drive unit 100 to be further suppressed.

In this embodiment, when viewed from the left and right of the vehicle body, the crankshaft rotation axis 1b is located at the midpoint of the motor connection Amg, which is a line connecting the first rotation axis 15b and the second rotation axis 17b, and the motor connection Amg is inclined at 45 degrees to the horizontal plane. This makes it possible to simultaneously reduce the dimensions of the drive unit 100 in the front-to-rear direction and the up-to-down direction.

The above describes embodiments of the present invention, but the above embodiments merely illustrate some of the application examples of the present invention and are not intended to limit the technical scope of the present invention to the specific configurations of the above embodiments.

Claims (5)

A drive unit having an electric unit including a first electric motor for driving, a reduction mechanism that transmits a rotational torque of the first electric motor to drive wheels, a second electric motor that is driven by an internal combustion engine to generate electricity, and a speed increasing mechanism that transmits the rotational torque of the internal combustion engine to the second electric motor,
the first electric motor, the reduction mechanism, the second electric motor, and the speed increasing mechanism are accommodated in one housing,
In the housing,
the first electric motor and the second electric motor are arranged in a front-rear direction of the vehicle body with their respective rotational axes parallel to each other,
The speed reduction mechanism and the speed increase mechanism are aligned in the front-rear direction of the vehicle body,
The electric unit and the internal combustion engine are connected in a state of being aligned in the left-right direction of the vehicle body,
a first rotating shaft which is a rotating shaft of the first electric motor and a second rotating shaft which is a rotating shaft of the second electric motor are located on the front and rear sides in the front-rear direction of the vehicle body, with a crankshaft rotating shaft which is a rotating shaft of the crankshaft of the internal combustion engine being interposed therebetween,
A drive unit, wherein the crankshaft rotation axis is located at a midpoint of a motor connection line that connects the first rotation shaft and the second rotation shaft when viewed from the left-right direction of the vehicle body. 2. The drive unit according to claim 1,
the electric unit and the internal combustion engine in a connected state are supported on the vehicle body from the left and right directions of the vehicle body by pendulum type mounts,
A drive unit in which a mount connection, which is a line connecting the support portion of the mount on the left side in the left-right direction of the vehicle body to the support portion of the mount on the right side in the left-right direction of the vehicle body, is parallel to the output shaft of the reduction mechanism. 3. The drive unit according to claim 2,
A drive unit, wherein the crankshaft rotation axis is parallel to the mount connection and lies on a vertical plane that includes the mount connection. 4. The drive unit according to claim 3,
the first electric motor is heavier than the second electric motor, and the speed increasing mechanism is heavier than the speed reducing mechanism;
A drive unit in which the center of gravity of the entire drive unit is located on the mount connection, by having the first electric motor and the reduction mechanism be arranged rearward of the vehicle body relative to the crankshaft rotational shaft, the second electric motor and the speed increase mechanism be arranged forward of the vehicle body relative to the crankshaft rotational shaft, and at least some of a plurality of auxiliary components of the internal combustion engine be arranged forward of the vehicle body relative to the crankshaft rotational shaft. 5. The drive unit according to claim 4,
A drive unit, wherein the motor connections are inclined at 45 degrees with respect to a horizontal plane when viewed from the left and right direction of the vehicle body.

Images